Dental engine



2- Sheets-Sheetb 1.

(No Model.)

J. H; K-IDDER.

DENTAL. ENGINE.

N0... $97,556:. Patented Feb. 12, 1889.

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(No Model.) 2 SheetsSheet 2. J. H. KIDDER.

. DENTAL ENGINE.

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JAMES H. KIDDER, OF LAXVRENCE, MAS$AGHUSETTS DENTAL ENGINE.

SPECIFICATION forming part of Letters Patent No. 397,556, dated February 12, 1889.

Application filed July 30, 1888. Serial No. 281,392. (No model.)

T0 at whom it may concern:

Be it known that I, J AMES H. KIDDER, of Lawrence, county of Essex, State of Massachusetts, have invented an Improvement in Dental Engines, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to dental engines of the class in which the operating-tool is revolved by means of power applied to a treadle normally resting upon the floor.

In dental engines as now commonly constructed a swinging arm extended substantially at a right angle to a standard or upright forms a bearing for a shaft to which is joined by a flexible connection a rod also united by a flexible connection to a toolholder, the said connected tool-holder, rod, and shaft bein g rotated by a belt or band passed about a driving-pulley supported by the standard or upright, and about a smaller pulley on the shaft supported in the swinging arm secured to the said standard or upright.

My invention has for one. of its objects to provide the flexible connection between the shaft and rod and between the rod and toolholder with a guard, to be described, by means of which the said flexible connection is prevented from buckling or vibrating when the tool is subjected to considerable opposition to its free rotation in operating'it.

Another feature of my invention consists in providing the engine with an arm pivotally secured to the standard and extended substantially at a right angle therefrom, the said arm having secured to or forming part of it the standard supporting the tool-shaft, whereby the operating-tool and its shaft may be turned into any desired position. The swinging arm, by reason of its being extended from the standard, enables the operating-tool to be brought more directly in front of a patient, to thereby obtain a better operating or working position and a wider range of movement of said tool. The swinging arm-may be readily swung around out of the way of the operator when not in use, thus leaving the op erator free to work unhindered without the necessity of moving the base of the machine.

Still another feature of my invention consists in providing an auxiliary pulley by which the band is retained in place upon the driving-pulley when the tool-operating shaft is brought near the floor, and also when the swinging arm is at an angle to the plane of p the driving-pulley.

Other features of my invention will be pointed out in the claims at the end of this specification.

Figure 1 is a rear end elevation of a dental engine embodying my invention; Fig. 2, a side elevation of the lower part of the machine shown in Fig. 1, partially broken off to save space in the drawings; Fig. 3, a detail on an enlarged scale of the guard for the flexible connection for the shaft; Fig. 4:, a section of Fig. 3 on line a: m,- Fig. 5, a view of the connection and rod shown in Fig. 3; and Fig. 6, an enlarged detail to show the connection between the tool-holder and rod.

The upright a, supporting the driving-pulley a, mounted on the shaft a and having the crank a connected by the rod a to a foot-treadle, a has secured to or forming part of it a hollow tube or standard, 60

The hollow tube or standard a receives within it a finger, a", on an arm, a", provided, as shown, with a vertical hollow extension, a into which is adj ust-ably fitted a rod, a", having fitted upon it a sleeve, a, provided with arms a which support a shaft, a having mounted on it between said arms, as shown in Fig. 1, a pulley, b, connected'by a band or belt, I), to the driving-pulley a, the said band being passed about an auxiliary double pulley, 6 mounted in a bracket, b secured to the standard a The shaft a is extended, as shown, through a hollow sleeve, 11 preferably secured to one of the arms a the said shaft being connected at its opposite end by a flexible medium, preferably a spiral spring, If, to a rod, 19 which is joined by a spring, 19 to a toolholder, b which is fitted into a sleeve, 5

To protect the spring b I have provided a guard consisting, as shown, of a sleeve, 0, free to turn on the shaft a and a sleeve, 0', on the rod 17 the said sleeves being joined by a loose or free connection, preferably by strips or links 0 0 a, hinged together and to the said sleeves, as shown in Figs. 3 and a, the strip or link 0 having an opening through which the spring b is extended, so that the links 0 c are on opposite sides of the said spring, the link 0 having secured to or forming part of it a guard or shield, 0 through which the spring is passed, the shield or guard sliding over the said spring when the latter is bent or straightened, the link 0 also constituting a guard or shield. The spring b is protected by a somewhat similar guard consisting of a sleeve, 0 movable on the rod b and united to the tool-holder by a springjoint formed by links or rods 0 c united by a spiral spring, 0 the said spring-joint constituting a universal joint to enable the tool to be moved in every direction.

\Vhen the rod b is turned to occupy different positions as the instrument is used, the links 0 c 0 become substantially straight, while the sleeve 0 slides on the rod 19 As the spring 11 is bent or straightened, according to the position in which the instrument is turned, the guards or shields c 0 move upon and guide the spring 11 thus preventing it from buckling or vibrating, and the said guards also prevent the spring from buckling when the tool meets with opposition to its free rotation.

The sleeve 0 is provided with a ing or projection, e, which strikes against a similar lug or projection, c, on the sleeve 6 when the rod 1) and tool are brought substantially in a straight line with the shaft the said lugs constituting a stop by which the sleeve 0 is prevented from rotating with the spring 11 and shaft a thus obviating buckling of the said spring.

The foot-treadle a is connected to the rod (t3 by a wire rod, f, extended through a slot in the rod a and detachably connected at one end to the said treadle. The foot-treadle a is hinged at one end to a foot, f, as shown, having secured to it a rod, f", (see Fig. 2,) connected by a hinge to a foot, f, the hinge having mounted on its pintle f an upright, f (see Fig. 1,) but which maybe connected to the rod f.

In operation. the foot-treadlc is normally in the position shown in Fig. 2 by full lines; but when the engine is not bein g used the treadle may be moved up out of the way into the dotted-line position, Fig. 2, by pressing with the foot upon the post f the rod a" sliding over the wire rod f, the said treadle being supported in its upright position by the rod f, assisted, as shown, by gravity.

The rod C69 is adjustably secured in the hollow extension a as shown in Fig. 1, by a collar, f secured to said rod by set-screw j, said collar resting upon said extension.

The arm (t is free to swing around in substantially a horizontal path, but is prevented from being lifted out of the hollow standard a by set-screw f having its end extended into an annular groove, f, in the finger to.

\Vhen the engine is not in use, the upper part may be dropped down by loosening the screw f, to permit the rod cr" to descend through the hollow extension a thus rendering the engine compact.

\Vhen the upper part of the engine is lowered, the pulley Z) prevents the band I) from falling away from the driving-pulley a, so that when the upper part of the engine is again raised into its operative position it is not necessary to adjust the. band on the driving-pulley.

I prefer to employ the horizontal arm a but, if desired, it may be dispensed with and the rod 6L9 inserted in to the hollow standard a The pulley a is prevented from stopping on the dead-centers, as herein shown, by a spring, f secured to a crank, f set substantially opposite to the crank (F.

I claim 1. In a dental engine, the combination, with a stationary upright or standard and a driving-pulley supported thereby, of the swinging arm a pivotally secured to the said standard near the said pulley, to move in a horizontal path with the standard as a center, a tool- 1 shaft, a tool connected thereto, a rod to support said tool-shaft, a pulley on the tool-shaft connected to the driving-pulley and secured to the swinging arm, to move with the said arm to permit the said tool-shaft and tool to be brought into different operative positions while the standard or upright remains unchanged, whereby the tool-shaft and tool may be brought nearer the patient without moving the standard or upright, substantially as described.

2. Ina dental engine, the combination, with an upright and a driving-shaft, a of a foottreadle connected to said shaft, a rod, f, connected to the foot-treadle and hinged or pivoted to the said upright, and a post, f connected to the rod f, whereby the foot-treadle may be moved into elevated position out of the way by pressure upon the post f substantially as described.

3. In a dental engine, the combination, with a driving-shaft, (6*, having a crank, of a foottreadle provided with a rod, f, a red, a secured to said crank, and through an opening in which the rod f is extended, and a rod, f secured to the under side of the treadle, as and for the purpose specified.

4. In a dental engine, the combination, with the shaft (1/ and rod 1'), of a spring, I), and a guard for said spring, consisting of sleeves c c, a shield, 0 and a hinged connection, substantially as described, hinged to said sleeves and connected to said shield, substantially as described.

5. In a dental engine, the combination, with a tool-shaft and a rod joined to said shaft by a flexible connection, of a tool-holder and a spring, b between said rod and tool-holder, a sleeve, 0, loose 011 said rod, and an independent flexible connection joining said sleeve and tool-holder, and consisting of rods 0 c and spring c", whereby buckling of the said spring is prevented, substantially as described.

(3. In a dental engine, the combination, with a tool-shaft, a, a sleeve, 5 to support said shaft, a lug, e, on said sleeve, a rod, 1), a spring, I)", and a guard for said spring, consisting of sleeves c c, a shield, 0 and links connected to said shield and jointed to said sleeves, and a lug, e, on the sleeve 0, to cooperate with the lug e, substantially as and for the purpose specified.

' 7. In a dental engine, the combination, with 

